Differentiation of electrical and contractile properties of slow and fast muscle fibres (original) (raw)
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Differentiation of slow and fast muscles in chickens
Cell and Tissue Research, 1977
1. The development of the characteristic histochemical appearance of the slow anterior latissimus dorsi (ALD) and fast posterior latissimus dorsi (PLD) was studied in chickens during embryonic development as well as during regeneration of minced muscle. 2. During embryonic development the activity of the oxidative enzyme succinic dehydrogenase (SDH) is higher in the slow ALD muscle already at 16 days of incubation. At this time the fast PLD has a higher activity of the glycolytic enzyme, phosphorylase. Although the histochemical appearance of the two types of muscle is already different at 16 days, their contractile speeds are still similar. No difference in myosin ATP-ase was found in the two muscles in young embryos but in 20-day old embryos the two muscles became distinctly different when stained for this enzyme. 3. When PLD muscles in hatched chickens redeveloped during regeneration in place of ALD the histochemical characteristics of the regenerated muscle resembled ALD, and when ALD regenerated in place of PLD it resembled PLI~. 4. It is concluded that the histochemical characteristics of slow and fast muscles become determined during early development, even before any difference in contractile properties can be detected and that they are determined by the nerve.
The influence of innervation on differentiating tonic and twitch muscle fibres of the chicken
The Journal of physiology, 1981
1. The anterior (ALD) and posterior (PLD) latissimus dorsi muscles of adult chickens were denervated by section of their motor nerves. Four weeks later the contractile and membrane properties of these muscles were studied in vitro at room temperature.2. Although the time course of the PLD muscle twitch was slightly prolonged, the qualitative difference in contractile characteristics of the slow ALD and the fast PLD muscles was maintained after denervation.3. The difference in the passive membrane characteristics of the ALD and PLD muscle fibres was not lost after denervation, although the membrane resistance (R(m)) and space constant (lambda) of the denervated muscles fell. The membrane resistance, space (lambda) and time (tau(m)) constants of the ALD muscle remained significantly greater than for the PLD muscle fibres. The absolute values of tau(m) in both muscles increased, implying that in the case of the ALD the membrane capacitance (C(m)) was increased above normal after denerv...
Differences in muscle fibre properties as a factor in “fast” and “slow” contraction in Carcinus
1963
An investigation was made of the electrical and mechanical responses to direct and indirect stimulation in Carcinus closer muscles. 2. Three main types of muscle fibre could be distinguished on the basis of electrical responses to indirect stimulation. They were called Types A, B and C. 3. Type A muscle fibres showed large "fast" p.s.p.'s and electrically excitable membrane responses, but usually no response to "slow" axon stimulation. Type B muscle fibres showed large, slowly decaying "slow" p.s.p.'s and small or no "fast" p.s.p.'s. In Type C muscle fibres "fast" and "slow" p.s.p.'s were both present. Both were small at low frequencies of stimulation of the motor axons but increased in size with increasing frequency of stimulation. 4. The electrical properties of the membranes of the three muscle fibre types were found to differ. Type A muscle fibres had low membrane resistances, small time constants and electrically excitable membranes. Type B muscle fibres had high membrane resistances, large time constants and electrically inexcitable membranes. Type C muscle fibres had intermediate properties. The electrical responses to indirect stimulation could be largely explained in terms of the membrane properties of the fibres from which they were recorded. 5. The average membrane potential at which detectable tension was developed by the muscle in response to potassium depolarization was 55 inV. 6. Tension was developed by single directly stimulated Type C muscle fibres when the depolarization at the current-passing microelectrode was 42 mV to 58 mV. 7. During both fast and slow contractions, electrical responses can be observed which exceed the estimated membrane potential threshold for ten~,ion development.
The mechanical and thermal properties of frog slow muscle fibres
The Journal of physiology, 1971
1. A study has been made of the mechanical behaviour and the heat production of frog slow muscle fibres in iliofibularis nerve-muscle preparations at 20 degrees C.2. The slow fibre isometric tension and its rate of development increase with stimulation frequency, the increases beyond 30 Hz being relatively small. Relaxation rate also increases with stimulation frequency. The tension-length curve and maximum isometric tension (250 mN.mm(-2)) are similar to those of twitch fibres. The maximum shortening velocity is estimated to be 0.11 tonus bundle lengths per second.3. For contractions up to 60 sec at 30-50 Hz the slow fibre heat rate is steady at 6 mJ.g(-1).sec(-1). Slow fibres produce aerobic recovery heat with a time course similar to that of twitch fibres.4. The accuracy of the results is discussed, and a comparison is made with the properties of twitch fibres. It is concluded that the tension-producing reactions are thirty times slower in the slow fibres.
Possible mechanisms determining synapse formation in developing skeletal muscles of the chick
Cell And Tissue Research, 1974
1. The development of endplates of the multiply innervated anterior latissimus dorsi (ALD) and focally innervated posterior latissimus dorsi (PLD) muscles was studied in chick embryos. The endplates were visualized using acetylcholinesterase (ACHE) stain. Endplates appear in both muscles between the 14th and 15th day of incubation, when the characteristic pattern of innervation is already distinct. 2. The effect of curare on the development of endplates of ALD and PLD muscles of the chick embryo was studied next. In the presence of curare the high concentration of AChE at the neuromuscular junction of ALD fails to develop, and is very much reduced in PLD. 3. This effect of curare is reversible, since when curare was discontinued for four days, endplates of normal appearance developed in ALD muscle. However their spacing was different from that of normal muscles, in that the distance between successive endplates was smaller in muscles from curarized embryos. 4. Muscle fibre diameters were measured in ALD and PLD muscles from control and curare-treated 20 days old embryos. The mean muscle fibre diameter of ALD was greater than that of PLD, and was reduced in both muscles by curare. 5. It is concluded that the responsiveness of the muscle membrane to the transmitter is essential for the development of connections between nerve and muscle, and that the density of innervation of a muscle fibre may be related to the size of its response to the transmitter and its spread along the fibre.
Slow and fast fatigable frog muscle fibres: electrophysiological and histochemical characteristics
General physiology and biophysics, 2005
Continuous activity of isolated frog gastrocnemius muscle fibres provoked by repetitive stimulation of 5 Hz was used as an experimental model for fatigue development in different fibre types. Parameter changes of the elicited intracellular action potentials and mechanical twitches during the period of uninterrupted activity were used as criteria for fatigue evaluation. Slow fatigable muscle fibre (SMF) and fast fatigable muscle fibre (FMF) types were distinguished depending on the duration of their uninterrupted activity, which was significantly longer in SMFs than in FMFs. The normalized changes of action potential amplitude and duration were significantly smaller in FMFs than in SMFs. The average twitch force and velocity of contraction and relaxation were significantly higher in FMFs than in SMFs. Myosin ATPase (mATPase) and succinate dehydrogenase activity were studied by histochemical assessment in order to validate the fibre type classification based on their electrophysiologi...
Contractile differentiation of foetal cattle muscles: intermuscular variability
Reproduction Nutrition Development, 1999
Contractile differentiation was studied in six foetal muscles exhibiting different contractile characteristics in adult cattle: the Masseter, Diaphragma, Biceps femoris, Longissimus thoracis, Semitendinosus and Cutaneus trunci. These muscles were excised from foetuses aged 60-260 days. Fibre types were identified by immunohistochemistry using three monoclonal antibodies raised against types 1, 2a, 2b (or 2x) and foetal myosin heavy chains. The different myosin isoforms were also separated by electrophoresis, identified by immunoblotting and quantified by ELISA. At least two generations of cells were observed in all the muscles studied. The primary, early differentiated one, gave rise to type II fibres in Cutaneus trunci and type I fibres in all remaining muscles. The secondary generation of cells differentiated later than the first generation of cells. Its pattern of differentiation was more complex in particular from 150 to 210 days. It formed slow fibres in slow adult muscles, fast fibres in fast adult muscles and both types in mixed muscles. Precocity of differentiation was muscle-type dependent and related to muscle function at birth. © Inra/Elsevier, Paris muscle / contractile differentiation / bovine / foetus Résumé ― Différenciation contractile chez le foetus bovin : variabilité entre muscles. La différenciation contractile durant le stade foetal (de 60 à 260 j) est étudiée dans six muscles différant par leurs caractéristiques chez l'adulte : le Masseter, Diaphragma, Biceps femoris, Longissimus thoracis, Semitendinosus et Cutaneus trunci. Le type de fibre est identifié par immunohistochimie à l'aide d'anticorps spécifique des isoformes lente (type 1), rapides (2a et 2b (ou 2x)) et foetale de chaînes lourdes de myosine. Celles-ci sont également séparées par électrophorèse, identifiées par immunoblotting et quantifiées par Elisa. Au moins deux générations de cellules sont observées dans tous les muscles. La première qui a une différenciation précoce donne naissance à des fibres rapides dans le Cutaneus trunci et à des fibres lentes de type 1 dans tous les autres muscles. La différenciation de la seconde génération est plus complexe, particulièrement entre 150 et 210 j. Elle donne naissance soit
Induction of the action potential mechanism in slow muscle fibres of the frog
The Journal of Physiology, 1971
The electrical and structural characteristics of 'slow' muscle fibres of the frog were studied in normal and denervated muscles, and in muscles undergoing re-innervation by a mixed nerve containing large and small motor axons. 2. In agreement with previous studies, slow fibres in normally innervated muscles were incapable of producing action potentials. 3. Approximately 2 weeks after the sciatic nerve was transacted or crushed, slow muscle fibres acquired the ability to generate action potentials. These fibres were positively identified as belonging to the slow type, because their passive-electrical and ultrastructural characteristics remained essentially unchanged after the operations. 4. The action potential mechanism induced in slow fibres is sodiumdependent, and is blocked by tetrodotoxin. 5. After long-term re-innervation by a mixed nerve, slow fibres lose their acquired ability to generate action potentials, presumably because small motor axons re-establish connexion with the fibres. 6. It is concluded that the action potential mechanism of slow muscle fibres is under neural control, and is normally suppressed by small motor axons.
Arquivos de Neuro-Psiquiatria, 1968
1. The whole biventer cervicis muscles of the chick, being innervated by a branch of the dorsal ramus of C, presents structural Deculiarities which recommend it as good skeletal muscle for embryological, anatomical, physiological and pharmacological neuro-muscular investigations. 2. The nerve trunk responsible for the innervation of the distal belly runs completely included within the intermediate tendon; therefore, a tendon transection determines complete denervation and nerve fibre degeneration of the distal belly of the muscle. 3. Long-time experimentally denervated distal bellies (from three up to twelve months) are repopulated by ectopic nerve fibres which must have arisen from a source other than the proximal stump, neighbour nerves or nervi-vasorum. 4. Motor endplates appear in these long-time (eight or more months) denervated biventer cervicis distal bellies. 5. Although atrophic-looking such muscle bellies responded to indirect and to direct electrical stimulation — 1.5 V —...
The Journal of physiology, 1984
Muscle activation patterns of embryonic chick hind limb muscles were determined from electromyographic (e.m.g.) recordings in an isolated spinal cord/hind limb preparation of stage 34-36 embryos, and were compared with in ovo e.m.g. activity from similarly staged embryos. Muscle activity in ovo consisted of periodically recurring sequences of bursts during which antagonistic muscles often alternated and synergistic muscles were co-active, as compatible with their mature function. However, more variable behaviour was also observed. Burst sequences in ovo were often initiated by a short-duration, high-amplitude discharge that occurred synchronously in all muscles studied, and which was followed by a period of electrical silence that was longest in the flexor muscles. This type of activity has not been described previously in mature animals. In ovo movement sequences were generally initiated by extensor activity which progressively declined in duration and intensity throughout the sequ...